This invention relates to noise reduction devices for textile machinery, and is particularly directed to the reduction of noise which results from the mounting of tape idlers in the textile machinery.
In known textile machinery, spindle tapes that drive the machinery spindles are directed over idler pulleys of a type known as Meadows tape idlers. In tape idlers of this type, the support for the idlers is comprised of a bracket having a pair of spaced apart square mounting slots. The pulley assembly itself was comprised essentially of a pair of plates on the sides of a rotatable pulley wheel, with a bearing held between the plates for rotatably supporting the pulley wheel. Square bosses or projections were provided on the plates, the projections being adapted to fit into the square slots of the brackets. The assembly of the two plates with their square projections, and the bearing between the plates, was held together by a central axially extending bolt.
These pulley assemblies are functionally satisfactory, and are known to give many years of service. They do present a problem, however, of introducing noise into the textile machinery room. For example, since the brackets and the plates with their square projections were metal, and since a loose fit was provided between these elements, the metal to metal contact resulted in the generation of noise. In addition, the cover plates, which fit adjacent to but do not touch the revolving pulley, act as resonators to magnify any noise that is generated.
While the noise generated by any single tape idler may not be excessive, the processing rooms, for example, for the production of thread or yarn, may contain hundreds or thousands of such tape idlers. As a consequence, the overall noise produced by the tape idlers may be very great. It is not unusual, in mills included in such tape idlers, for the noise levels in a room to exceed 90db.
There are of course many well known noise reducing techniques, and modern textile equipment may readily be designed to take advantage of such techniques, to reduce the room noise levels to tolerable values. The useful life of textile machinery, such as thread and yarn spinning frames and the like, is quite long, however, so that full replacement of the equipment is neither economically justified nor warranted.
There has been recent interest in the reduction of noise level in factories, from the standpoint of safety and health, and standards have been established with respect to the length of time that a worker may be present in a room at given noise levels. The noise level in the rooms of a textile mill has been adequately high in the past, that workers were not permitted to spend full working days in the rooms, without earmuffs or the like. This is of course undesirable from a standpoint of operating and maintaining the equipment, since, particularly, with less modern equipment, manual operation such as doffing and donning may be required. The solution of requiring the workers to wear earmuffs has not been found to be satisfactory or acceptable to the workers.
The present invention is therefore directed to the provision of noise reduction means, for reducing the above described spindle noise in textile machines. While the invention is particularly directed to the provision of noise reducing means that may readily and economically be employed on existing equipment, it will of course be apparent that the invention contemplates the application of the same concept to new equipment, if desired.
Briefly stated, in accordance with the invention, tape idlers of the above type are modified, without requiring modification of the brackets. In accordance with the invention, the plates on the pulley assemblies are replaced by plastic rods which engage the sides of the bearing. The diameters of the rods are less than the minimum dimension of the square slots in the brackets, and a bolt is provided extending through the rods and the bearing, to hold these elements together. In addition, a resilient sleeve, for example, of rubber, is provided at the axially outer end of the rods, the sleeves having diameters such that the axial ends of the assembly may be readily forced into the square slots. In this arrangement, the bearing is preferably force fit into the pulley wheel itself, and the pulley may be identical to the pulleys that had previously been employed.
As a result of such modification of the tape idler pulleys, metal to metal contact at the bracket is avoided, and this source of noise is hence removed. In addition, since the plates themselves are no longer employed, this source of noise is also removed.
In a particularly advantageous embodiment of the invention, a kit is provided including those parts which, as a minimum, should be replaced in order to reduce the noise generated by the tape pulley assembly. Specifically, the kit includes two plastic rods and the resilient sleeves adapted to fit over the rods, and be in turn fit into the bracket slots. These rods and sleeves replace the end plates of the previously employed pulley assemblies. In addition, a new bearing may be provided, as well as a bolt for holding these elements together. It has not been found generally necessary to replace the pulley wheel itself, since such pulley wheels, especially if they are plastic, will generally not need replacement.